Technical Field
The present disclosure relates to an organic light-emitting device. More specifically, the present disclosure relates to an organic light-emitting device having a 2-stack structure that can achieve a desired color quality while improving efficiency and lifespan.
Description of the Related Art
An organic light-emitting display (OLED) apparatus is a self-luminance display apparatus. An OLED apparatus utilizes an organic light-emitting device in which electrons from a cathode and holes from an anode are injected into an emission layer, and the electrons and holes recombine to form excitons, such that light is emitted when the excitons change from an excited state to the ground state.
OLED apparatuses can be sorted into a top emission OLED apparatus, a bottom emission OLED apparatus, and a dual emission OLED apparatus depending on the direction in which light exits. Further, OLED apparatuses can be sorted into an active matrix OLED apparatus and a passive matrix OLED apparatus depending on the driving manner.
An OLED apparatus does not require a separate light source, unlike a liquid crystal display (LCD) apparatus. Thus, the OLED apparatus can be made lighter and thinner than an LCD apparatus. Further, an OLED device has advantages in that it is driven with low voltage to consume less power, and in that it can represent vivid colors, has short response time, wide viewing angle, and a good contrast ratio (CR). For these reasons, an OLED device is currently under development as the next generation display device.
As high-definition displays become more prominent, the number of pixels per area increases, and high luminance is required. However, the electric current per area is limited by the structure of an OLED apparatus. In addition, as the amount of applied current increases, reliability of an OLED display is degraded, and power consumption increases.
Accordingly, in order to improve quality and productivity of OLED apparatuses, it is necessary to overcome certain technical limitations such as luminous efficiency, lifespan, and power consumption of organic light-emitting devices. There are a variety of on-going research activities with respect to organic light-emitting devices capable of improving luminous efficiency, lifespan, and viewing angle without compromising desired color quality.